Bengie, as I recall there were a number of changes beteween the certification articles and production. Among them were fewer wing ribs resulting in some loss of torsional stiffness, the ommision of a "glove" at wing root and I think some simplification of the fin attachment.
I could be wrong in this, but I think this airplane employed a GAW airfoil, which was quite intolerant of any distortions. I know you can grab a wing tip and twist the wing with not too much force, resulting in some oil canning.
I believe there was at least one AD, if not more, calling for stall strips. The Tomahawk does have a lot of stall strips.
Piper does say that non-standard techniques may be required to accomplish spin recovery. The Aviation Consumer article of some years ago related a story of a couple of test pilots, maybe FAA, who got into a flat spin and were obliged to get up and lean over the instrument panel to get the CG far enough foward to recover. I guess that qualifies as a non-standard procedure. My hat is off to those guys!
William Kierschner probably has more time spinning 150s than I have total time, and gives it a clean bill of health, at least in stock form. William Thompson, ex Cessna manager of flight test, states that large engine conversions tend to go flat due to a greater polar moment of inertia due to the battery in the tail cone for CG purposes.
Geo.
